Forrest Mims Interview

Whit

Here is the link for an Amp Hour interview with electronic's guru Forrest Mims - http://traffic.libsyn.com/theamphour/TheAmpHour-171-SnellSolisequiousScientist.mp3

Heater.

Thanks for reminding me of the Amp Hour Whit.

Or go straight to the The Amp Hour page for the original http://www.theamphour.com/171-an-interview-with-forrest-mims-snell-solisequious-scientist/. There is a great picture of Forrest launching a rocket there.

It's a great interview, recommended.

Be warned there are hundreds of Amp Hour sessions there including a lot of interviews with some very interesting people. This can take up a lot of your life!

Then of course you need to catch up with the Dave Jones EEVBlog on YouTube https://www.youtube.com/user/EEVblog/featured

erco

Amazing fellow! Whit's link didn't work, but I found it at http://www.theamphour.com/?powerpress_pinw=3312-podcast

msrobots

@whit's link worked for me, and I really enjoyed it.

Very relaxed interview. The way it should be.

Worth listening!

Mike

Clock Loop

Using the discovery by Forrest Mims,"that LED junctions can detect light", I created a prop design that reflects this property.
I call it the MimsMirror. Because the same led that is used for emission, also is used for detection. The LED acts similar to a mirror with this circuit.

So technically, If you have a TV made out of very tiny LED's, and used an array of processors capable of detecting the leds junction falloff rate, you could make a video phone that was bi-directional, live, and in HD.
This would be a tv-phone. It would use the tv led array as the camera.

So technically a tv made like this could see you, and if no one told you..... just pay attention to those internet connected tvs, and bi-directional tv connections.... wink wink.

It is a discovery that leads to optical processors.
As the absorption efficiency increases, while maintaining emission efficiency, optical capacitors(memory) are possible.



You tube won't let my counts go above 301 on this vid. Been like that for almost a year now, I even asked them to reset it or something.

The link to the programming(parallax forum link) is in the youtube videos description.

Each circuit would not function for longer than the programs cycle time of about 3 or less seconds(during which time the leds become emitters), if the concept was never discovered by Forrest Mims and then a program written, and a circuit designed to take advantage of this property of the led junction.

If the leds also didn't detect light, none of the circuits would be "triggered" to then run through the 3 or less second cycle of emitting light. The emission length is actually determined by pseudo-random sequencer to modulate the PLL's target phase. The PLL responds by speeding up and slowing down in a an endless effort to lock. This results in very unpredictable frequency jitter which is fed back into the sequencer to keep the bit salad tossing. The final output is a truly-random 32-bit unbiased value. This value is then limited to be as big as 1 second and as small as 1/4 second. The direction the leds rotate in left to right or right to left is also determined by this same pseudo-random sequencer. The direction and length is different for each color also.

The propeller chip is fast enough for led junction detection and has enough "gizmos" to do truly random work,,, all these things in one package.

Heater.

Clock Loop,

Whilst Forrest has done a lot of interesting things with the light detecting possibilities of LEDs, especially exploiting their spectral response for various purposes, I'm not sure we should claim that he discovered the phenomena.

This all operates via the photo-electric effect which was essentially discovered by Heinrich Hertz in 1887, worked on by Max Planck and others. Einstein got his Nobel Prize for his theory of the photo-electric effect.

It's Hertz discovery of the photo-electric effect that led to quantum mechanics and eventually to the LEDs that Mims uses.

I do credit Mims with a lot of very smart "out of the box thinking" though. Exploring the ways things can be used other than those intended. A true Hacker. Exploiting the narrow band light response of different LEDs so as to be able to analyse the atmosphere is damn clever.

Clock Loop

Heater. wrote: »

Clock Loop,

Whilst Forrest has done a lot of interesting things with the light detecting possibilities of LEDs, especially exploiting their spectral response for various purposes, I'm not sure we should claim that he discovered the phenomena.

This all operates via the photo-electric effect which was essentially discovered by Heinrich Hertz in 1887, worked on by Max Planck and others. Einstein got his Nobel Prize for his theory of the photo-electric effect.

It's Hertz discovery of the photo-electric effect that led to quantum mechanics and eventually to the LEDs that Mims uses.

I do credit Mims with a lot of very smart "out of the box thinking" though. Exploring the ways things can be used other than those intended. A true Hacker. Exploiting the narrow band light response of different LEDs so as to be able to analyse the atmosphere is damn clever.

Yea, i suppose many people discovered the same things at the same time all the time, because life.

So perhaps, our society should be structured around something other than patents and I.P.
The rule being all things are open source.

It currently operates off who has access to capital.
Most do not.
You can't even get patents or I.P. without capital.
So the ones who have the ability to be published/funded/invested/etc///, win? Yea, actually. Unfortunately.

Heater.

Clock Loop,

I'm at a loss here. What has patents, the structure of society and capitalism got to do with what I said that you have quoted there?

I was just pointing out that the fact that metals and semiconductors generate current when exposed to light is a very well known phenomena that has been studied for decades (Since Hertz).

That is how photo transistors and photo diodes work. It's how solar cells work. As kids we used to scrape the black paint off of OC71 transistors to make our own light detectors. Anyone who has been around electronics may well have had the experience of some circuit being unexpectedly light sensitive. Often down to a glass encapsulated diode in a sensitive position.

So the whole idea of Mims "discovering" this for LEDs and calling it the "Mims effect" seems rather misplaced to me.

The clever part of what he did is to use the spectral response of different LEDs as a means to determine air quality.

So the ones who have the ability to be published/funded/invested/etc///, win? Yea, actually. Unfortunately.

I'm not sure I get what you are calling unfortunate.

In mathematics we have thousands of proofs and theorems etc named after famous Mathematicians. The idea seems to be to name the thing after the guy who discovered or proved it. When referring to a complex idea it's useful to have a name for it and it's natural to use the name of the guy who brought it to attention. Besides credit where it is due is a good thing.

And so it goes in Physics, biology and other fields.

One can debate if the right name is used of course. It's not really sure that Pythagoras was the discoverer of the triangle theorem or just that it was included in writings with Pythagoras name on it, for example.

To come up with "Mims effect" is to be ignorant of, or wilfully ignore, a century of physics that most school kids would know.

Bob Lawrence (VE1RLL)

I enjoyed the interview and have learned a bunch from his various books over the years. I always enjoyed the fact that his books were to the point and had a very few errors (I personally never found any)

Clock Loop

Heater...

You are at a loss because you are trying too hard.

Not once did I ever say mims discovered the photo electric effect.

(did you even notice the Q.E.D. book in the background of the video i attached to this thread?)

I said he discovered that an object, an L.E.D., can sense light.

I even put it in quotes to imply that its a quote so don't take to too seriously.

Then you started saying I am calling it the "Mims effect".
I have no idea where you got that from. I actually searched my threads for this exact quote, and nothing...



I never said he is the only one to discover this, he is just the one person, most people in this community got the idea from.

And if you followed the link in the video to the parallax forum thread on this device, you will see I actually state that he popularized this information.

Many scientific theories have been postulated and proven, but not all methods of proving that those theories are correct, have been discovered.

Popularizing an idea, is actually more important than the discovery its self, IMO.

Heater.

Clock Loop,

What you said was:

Using the discovery by Forrest Mims,"that LED junctions can detect light",

Which to the inattentive reader, like myself, comes awfully close to what I'm disputing here.

It perpetuates what we read many times, for example wikipedia:
"...he was the first person to realize that light-emitting diodes (LEDs) had the ability to not only emit light, but also to sense light.[49] This dual-action (emission/detection) of LEDs or “Mims Effect” was unknown before his discovery"

Well, I could be wrong but I don't buy it.

My apologies if that was not your meaning.

Popularizing an idea, is actually more important than the discovery its self, IMO.

Mims, certainly did a very good job with that. Along with all the other things he wrote about over the years.

Chris Savage

Thanks for the link! That's one I wouldn't want to miss. I credit Forrest Mims with focusing my interest in electronics. His notebooks and manuals through Radio Shack in the 80s turned me on to electronics in a way no other text had done before.

erco

As I mentioned elsewhere, I credit Forrest's Shack books with guiding me through several milestones in my life. I won the high school science fair and later got my job at Mattel with projects gleaned directly from those circuit manuals. He remains a hero and role model for me.

It's still a treat to review his Engineer's Notebook periodically. I get new ideas for projects by seeing the breadth and scope of his many varied applications. Missing pulse detector, FSK data transmitter, programmable light meter, sample & hold circuit. Digital, analog, he covered it all.